Conditioner of chemical-mechanical polishing station

ABSTRACT

A conditioner for conditioning the polishing pad of a chemical-mechanical polishing station. The conditioner includes a conditioning disk having an input surface and an output surface, a tube with one end attached to the input surface of the conditioning disk, a high-pressure fluid supplier connected to the other end of the tube and a plurality of nozzles positioned on the output surface of the conditioning disk.

BACKGROUND OF INVENTION

[0001] 1. Field of Invention

[0002] The present invention relates to a chemical-mechanical polishing (CMP) station. More particularly, the present invention relates to the conditioner of a chemical-mechanical polishing station.

[0003] 2. Description of Related Art

[0004] Chemical-mechanical polishing (CMP) is a major global planarizing technique. The irregular surface of a wafer is planarized through mechanical grinding normally with the assistant of a chemical reagent.

[0005]FIG. 1 is a simplified top view of a conventional chemical-mechanical polishing station. FIG. 2 is a side view of a conventional chemical-mechanical polishing station.

[0006] As shown in FIGS. 1 and 2, the chemical-mechanical polishing station includes a polishing table 100, a polishing pad 102, a wafer carrier 104, a slurry tube 108 and a conditioner 110.

[0007] The polishing pad 102 is laid over the polishing table 100. The wafer carrier 104 is placed on the polishing pad 102. The wafer carrier 104 grips a wafer 106 and presses the wafer 106 against the polishing pad 102 in a polishing session. The slurry tube 108 is placed over the polishing pad 102 so that slurry is delivered to the polishing pad 102 during a polishing operation. The conditioner 110 is also positioned over the polishing pad 102. Hard particles such as diamond or ceramic grits are embedded on the under surface of the conditioner 110 for conditioning the upper surface of the polishing pad 102.

[0008] To conduct a chemical-mechanical polishing operation, the polishing table 100 and the wafer carrier 104 both rotate in a pre-defined direction. The wafer carrier 104 grips the backside of the wafer 106 so that the front surface of the wafer 106 presses against the polishing pad 102. In the meantime, the slurry tube provides a continuous supply of slurry to the polishing pad 102. The protruding peaks on the front surface of the wafer 106 in contact with the polishing pad 102 react chemically with the reagent in the slurry. Together with the abrasive action of the abrasive particles in the slurry, the protruding peaks on the front surface of the wafer 106 are gradually removed. After conducting such chemical reaction and abrasive action for some time, the entire front surface of the wafer 106 is planarized.

[0009] In general, the upper surface of the polishing pad 102 is gritty having a degree of roughness between 1 to 2 μm. However, the upper surface of the polishing pad 102 may also be polished after polishing a few pieces of wafers so that the polishing capacity of the polishing pad is lowered. Moreover, residual material from the wafers 106 may accumulate over the polishing pad 102 leading to a change of polishing power. To remove the residual wafer material and to reconstitute the roughness of the polishing pad 102, the upper surface of the polishing pad 102 is re-conditioned using the conditioner 110 after the polishing pad 102 has polished a batch of wafers.

[0010] The conditioner 110 of a conventional chemical-mechanical polishing station generally includes a conditioning disk 112 with hardened particles (such as diamond or ceramic grits) embedded on the conditioning surface of the conditioning disk 112. Yet, if any of the hardened particles should drop onto the polishing pad 102 while the wafer 106 is being polished, the wafer 106 will be scratched and damaged.

SUMMARY OF INVENTION

[0011] Accordingly, one object of the present invention is to provide a conditioner for a chemical-mechanical polishing station that prevents any hard particles from dropping and hence damaging a polishing wafer.

[0012] To achieve these and other advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, the invention provides a conditioner for a chemical-mechanical polishing station. The conditioner includes a conditioning disk, a tube, a high-pressure fluid supplier and a plurality of nozzles. The conditioning disk has an input surface and an output surface. One end of the tube is connected to the input surface of the conditioning disk and the other end of the tube is connected to the high-pressure fluid supplier. The nozzles are positioned on the output surface of the conditioning disk. In this invention, the high-pressure fluid supplier can be a provider of high-pressure liquid or compressed air. The high-pressure liquid includes water and the compressed air includes nitrogen. The high-pressure liquid or compressed air from the high-pressure fluid supplier has a liquid or gaseous pressure preferably between 10 psi to 100 psi. The conditioner utilizes pressurized liquid or gases emitted from the nozzles to recondition a polishing pad so that the any residual wafer material lodged on the pad surface is removed and roughness of the pad surface is reconstituted.

[0013] This invention also provides a chemical-mechanical polishing station that includes a polishing table, a polishing pad, a wafer carrier, a slurry tube and a conditioner. The polishing pad is laid over the polishing table. The wafer carrier is placed on the polishing pad. The wafer carrier grips a wafer and presses the wafer against the polishing pad in a polishing session. The slurry tube is placed over the polishing pad so that slurry is delivered the polishing pad during a polishing operation. The conditioner is also positioned over the polishing pad for conditioning the upper surface of the polishing pad. The conditioner includes a conditioning disk, a tube, a high-pressure fluid supplier and a plurality of nozzles. The conditioning disk has an input surface and an output surface. One end of the tube is connected to the input surface of the conditioning disk and the other end of the tube is connected to the high-pressure fluid supplier. The nozzles are positioned on the output surface of the conditioning disk. In this invention, the high-pressure fluid supplier can be a provider of high-pressure liquid or compressed air. The high-pressure liquid includes water and the compressed air includes nitrogen. The high-pressure liquid or compressed air from the high-pressure fluid supplier has a liquid or gaseous pressure preferably between 10 psi to 100 psi. After polishing a few wafers, the polishing pad of the chemical-mechanical polishing station is reconditioned by the conditioner. To recondition the polishing pad, pressurized liquid or gas is emitted from the nozzles on the output surface of the conditioning disk so that any residual wafer material lodged on the pad surface is removed and roughness of the pad surface is reconstituted.

[0014] Since pressurized liquid or gas is used to recondition the polishing pad, the dropping of hard particles from a conventional conditioner onto the polishing pad is prevented and thus possible damage to the wafer is greatly minimized. Moreover, the conditioner has a relatively simple structure. Therefore, the invention may increase wafer yield without incurring too much additional cost.

[0015] It is to be understood that both the foregoing general description and the following detailed description are exemplary, and are intended to provide further explanation of the invention as claimed.

BRIEF DESCRIPTION OF DRAWINGS

[0016] The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. In the drawings,

[0017]FIG. 1 is a simplified top view of a conventional chemical-mechanical polishing station;

[0018]FIG. 2 is a side view of a conventional chemical-mechanical polishing station;

[0019]FIG. 3 is a simplified top view of a chemicai-mechanicai polishing station according to one preferred embodiment of this invention;

[0020]FIG. 4 is a side view of a chemical-mechanical polishing station according to one preferred embodiment of this invention;

[0021]FIG. 5 is a bottom view of the conditioner of a chemical-mechanical polishing station according to one preferred embodiment of this invention; and

[0022]FIG. 6 is a side view of the conditioner of a chemical-mechanical polishing station according to one preferred embodiment of this invention.

DETAILED DESCRIPTION

[0023] Reference will now be made in detail to the present preferred embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers are used in the drawings and the description to refer to the same or like parts.

[0024]FIG. 3 is a simplified top view of a chemical-mechanical polishing station according to one preferred embodiment of this invention. FIG. 4 is a side view of a chemical-mechanical polishing station according to one preferred embodiment of this invention. As shown in FIGS. 3 and 4, the chemical-mechanical polishing station includes a polishing table 100, a polishing pad 102, a wafer carrier 104, a slurry tube 108 and a conditioner 220.

[0025] The polishing pad 102 is laid over the polishing table 100. The wafer carrier 104 grips a wafer 106 and presses the wafer 106 against the polishing pad 102. The wafer carrier 104 includes a plurality of vacuum holes (not shown) for gripping the wafer 106 and a retaining ring (not shown) for limiting horizontal wafer movement. The slurry tube 108 is placed over the polishing pad 102 so that slurry is delivered to the polishing pad 102 during a polishing operation. The conditioner 220 is also positioned over the polishing pad 102 for conditioning the upper surface of the polishing pad 102 so that any residual wafer material lodged on the pad surface is removed and roughness of the pad surface is reconstituted.

[0026]FIG. 5 is a bottom view of the conditioner of a chemical-mechanical polishing station according to one preferred embodiment of this invention. FIG. 6 is a side view of the conditioner of a chemical-mechanical polishing station according to one preferred embodiment of this invention. As shown in FIGS. 4, 5 and 6, the conditioner 220 on the chemical-mechanical polishing station includes a conditioning disk 200, a tube 204, a high-pressure fluid supplier 210 and a plurality of nozzles 202 (as shown in FIG. 5) on the conditioning disk 200. The conditioning disk 200 has an input surface 200 a and an output surface 200 b (shown in FIG. 6). One end of the tube 204 is connected to the input surface 200 a of the conditioning disk 200. The other end of the tube 204 is connected to the high-pressure fluid supplier 210. The nozzles 202 are positioned on the output surface 200 b of the conditioning disk 200.

[0027] The high-pressure fluid supplier 210 in the conditioner 220 can be a pressurized liquid or gaseous provider. The pressurized liquid supplier 210 provides a liquid 206 such as water or some other suitable liquid. The pressurized gas supplier 210 provides a gas 206 such as nitrogen or some other suitable gas. The pressurized liquid or gas from the high-pressure fluid supplier 210 has a pressure preferably between 10 psi to 100 psi. After polishing a few wafers, the polishing pad 102 on the chemical-mechanical polishing station is reconditioned by the conditioner 220. To recondition the polishing pad 102, pressurized liquid or gas 206 is emitted from the nozzles 202 on the output surface 200 b of the conditioning disk 200 so that any residual wafer material lodged on the pad surface is removed and roughness of the pad surface 102 is reconstituted. In other words, high-pressure liquid or gas provided by the high-pressure fluid supplier 210 is transferred to the conditioning disk 200 via the tube 204 and ejected from the nozzles 202 of the conditioner 220 directly against the polishing pad 102 with great pressure. Hence, surface roughness on the polishing pad 102 necessary for a polishing operation is reconstituted and any residual material adhering to the polishing pad 102 is removed.

[0028] In this invention, the conditioner 220 of the chemical-mechanical polishing station no longer uses a surface impregnated with hardened particles to recondition the surface of the polishing pad 102. Instead of a physical surface, this invention uses jets of pressurized liquid or gas 206 to recondition the polishing pad 102. Hence, damage to the wafer 106 due to the dropping of hardened particles onto the polishing pad 102 no longer occurs. Ultimately, reconditioning the polishing pad 102 using the conditioner 220 in this invention will reduce wafer damage and increase wafer yield.

[0029] In summary, major advantages of this invention include:

[0030] 1. Pressurized liquid or gas is used to recondition the polishing pad. Hence, the dropping of hard particles from a conventional conditioner onto the polishing pad is prevented and possible damage to the wafer is greatly minimized.

[0031] 2. The conditioner has a relatively simple structure. Therefore, the invention may increase wafer yield without incurring too much additional cost.

[0032] It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the present invention without departing from the scope or spirit of the invention. In view of the foregoing, it is intended that the present invention cover modifications and variations of this invention provided they fall within the scope of the following claims and their equivalents. 

1. A conditioner for conditioning the polishing pad of a chemical-mechanical polishing station, comprising: a conditioning disk having an input surface and an output surface; a tube having one end connected to the input surface of the conditioning disk; a high-pressure fluid supplier connected to the other end of the tube; and a plurality of nozzles on the output surface of the conditioning disk.
 2. The conditioner of claim 1, wherein the high-pressure fluid supplier is a pressurized liquid supplier.
 3. The conditioner of claim 2, wherein the pressurized liquid supplier provides a pressurized liquid including water.
 4. The conditioner of claim 2, wherein the pressurized liquid supplier provides a liquid at a pressure between 10 psi to 100 psi.
 5. The conditioner of claim 1, wherein the high-pressure fluid supplier is a pressurized gas supplier.
 6. The conditioner of claim 5, wherein the pressurized gas supplier provides a pressurized gas including nitrogen.
 7. The conditioner of claim 5, wherein the pressurized gas supplier provides a gas at a pressure between 10 psi to 100 psi.
 8. A chemical-mechanical polishing station, comprising: a polishing table; a polishing pad over the polishing table; a wafer carrier over the polishing pad for gripping a wafer and pressing the front surface of the wafer against the upper surface of the polishing pad; a slurry tube over the polishing pad for delivering slurry to the polishing pad; and a conditioner over the polishing pad for conditioning the polishing pad, wherein the conditioner further includes: a conditioning disk having an input surface and an output surface; a tube having one end connected to the input surface of the conditioning disk; a high-pressure fluid supplier connected to the other end of the tube; and a plurality of nozzles on the output surface of the conditioning disk.
 9. The polishing station of claim 8, wherein the high-pressure fluid supplier is a pressurized liquid supplier.
 10. The polishing station of claim 9, wherein the pressurized liquid supplier provides a pressurized liquid including water.
 11. The polishing station of claim 9, wherein the pressurized liquid supplier provides a liquid at a pressure between 10 psi to 100 psi.
 12. The polishing station of claim 8, wherein the high-pressure fluid supplier is a pressurized gas supplier.
 13. The polishing station of claim 12, wherein the pressurized gas supplier provides a pressurized gas including nitrogen.
 14. The polishing station of claim 12, wherein the pressurized gas supplier provides a gas at a pressure between 10 psi to 100 psi. 